{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,27]],"date-time":"2026-10-27T17:11:04Z","timestamp":1793121064483,"version":"4.5.0"},"reference-count":40,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T00:00:00Z","timestamp":1771545600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"\n Objective<\/jats:title>\n \n Investigate the genetic background of porin OmpK35\/36 in\n Klebsiella pneumoniae<\/jats:italic>\n and their influence on antimicrobial susceptibility, particularly carbapenems and ceftazidime-avibactam (CZA).\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n 1407\n K. pneumoniae<\/jats:italic>\n genomes in GenBank were selected for analyzing outer membrane protein-related genes through BLAST method, including\n ompK35<\/jats:italic>\n ,\n ompK36<\/jats:italic>\n ,\n ompK26<\/jats:italic>\n ,\n ompK37<\/jats:italic>\n ,\n ompA<\/jats:italic>\n ,\n ompR<\/jats:italic>\n , and carbapenemase genes, including\n bla<\/jats:italic>\n KPC<\/jats:sub>\n ,\n bla<\/jats:italic>\n VIM<\/jats:sub>\n ,\n bla<\/jats:italic>\n IMP<\/jats:sub>\n ,\n bla<\/jats:italic>\n NDM<\/jats:sub>\n ,\n bla<\/jats:italic>\n OXA-48<\/jats:sub>\n . Using MEGA 11.0, OmpK35\/36 and\n ompK35\/36<\/jats:italic>\n phylogenetic trees were built among serotypes K1 and K2 strains. Further, serotype K1 NTUH-K2044 and\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n were used to construct mutants to elucidate impacts of OmpK35\/36 on drug-resistance.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n The rates of\n ompK35<\/jats:italic>\n ,\n ompK36<\/jats:italic>\n ,\n ompK26<\/jats:italic>\n ,\n ompK37<\/jats:italic>\n ,\n ompA<\/jats:italic>\n , and\n ompR<\/jats:italic>\n in\n K. pneumoniae<\/jats:italic>\n strains were 97.5%, 99.3%, 99.5%, 99.4%, 99.9%, and 100.0% respectively. The sequence similarities of OmpK35\/36 and\n ompK35\/36<\/jats:italic>\n were both over 90.0%.\n K. pneumoniae<\/jats:italic>\n strains with abnormal\n ompK35\/36<\/jats:italic>\n presented higher rates of carbapenemase genes than those with normal\n ompK35\/36<\/jats:italic>\n . As to \u0394\n ompK36<\/jats:italic>\n , the minimum inhibitory concentrations (MICs) of piperacillin, cefoxitin, cefazolin, cefuroxime, and imipenem increased to 4, 4, 4, 8, and 4 times respectively compared with those against NTUH-K2044; the MICs of piperacillin, cefoxitin, cefazolin, cefuroxime, imipenem, and meropenem increased to 8, 32, 32, 16, 8, and 8 times in \u0394\n ompK35\/36<\/jats:italic>\n respectively. The deletions of\n ompK35\/36<\/jats:italic>\n , especially the double deletion, would greatly help NTUH-K2044+\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n induce resistance to certain \u03b2-lactams. Further, the absence of\n ompK35\/36<\/jats:italic>\n elevated the MIC of CZA against NTUH-K2044+\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n .\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n \n Highly conserved\n ompK35\/36<\/jats:italic>\n are widely present in\n K. pneumoniae<\/jats:italic>\n strains. The loss of OmpK35\/36 confers increased resistance to certain \u03b2-lactams, with OmpK36 being dominant. Moreover, OmpK35\/36 loss is a contributor but not a determinant in the formation of carbapenem-resistance under the absence of\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n , as well as in the formation of CZA-resistance with one\n bla<\/jats:italic>\n KPC-2<\/jats:sub>\n .\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fcimb.2026.1735799","type":"journal-article","created":{"date-parts":[[2026,2,20]],"date-time":"2026-02-20T06:41:23Z","timestamp":1771569683000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["OmpK35\/36 absence does not confer carbapenem-resistance alone nor ceftazidime-avibactam resistance with one blaKPC-2"],"prefix":"10.3389","volume":"16","author":[{"given":"Susu","family":"Wu","sequence":"first","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]},{"name":"Taizhou Key Laboratory of Infection and Tumor Immunology","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yinyin","family":"Yang","sequence":"additional","affiliation":[{"name":"Endoscopy Center of Taizhou Hospital Affiliated to Wenzhou Medical University","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wanyao","family":"Xiang","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jin","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]},{"name":"Taizhou Key Laboratory of Infection and Tumor Immunology","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xinhua","family":"Luo","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]},{"name":"Taizhou Key Laboratory of Infection and Tumor Immunology","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mengqiao","family":"Xu","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dakang","family":"Hu","sequence":"additional","affiliation":[{"name":"Department of Laboratory Medicine, Taizhou Municipal Hospital (Taizhou University Affiliated Municipal Hospital), School of Medicine, Taizhou University","place":["Taizhou, Zhejiang, China"]},{"name":"Taizhou Key Laboratory of Infection and Tumor Immunology","place":["Taizhou, Zhejiang, China"]},{"name":"Key Laboratory of Sepsis of Taizhou","place":["Taizhou, Zhejiang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haifang","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Clinical Laboratory, the Second Affiliated Hospital of Soochow University","place":["Suzhou, Jiangsu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,2,20]]},"reference":[{"key":"B37","doi-asserted-by":"publisher","first-page":"8376","DOI":"10.1021\/acs.jpcb.4c03327","article-title":"Molecular Mechanism of Ciprofloxacin Translocation Through the Major Diffusion Channels of the ESKAPE Pathogens Klebsiella pneumoniae and Enterobacter cloacae","volume":"128","author":"Acharya","year":"2024","journal-title":"J. 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